Slow Cooker French Onion Soup

This Slow Cooker French Onion Soup is such an easy and delicious recipe! A classic French Onion Soup prepared in the crockpot and loaded with incredible flavor, caramelized onions, and CHEESE!

Flavorful Crockpot French Onion Soup Recipe

This fantastic Slow Cooker French Onion Soup makes a hearty meal and it’s SO easy to make, especially since the slow cooker/crock pot does all the work! Start the soup the night before and come home to a ready-made dinner.

Friends, I have been updating my older recipes on Diethood, and my photos, for the past 3 months like it’s nobody’s business, and this Slow Cooker French Onion Soup finally got to see its new and improved version since its time when I first introduced it to you in November of 2012! Can’t believe I’ve been at this food blog shenanigans for like, 6 years. WOOOT! HIGH FIVES, please!

French Onion Soup bowls.

Okay, so, anyhow!

SLOW COOKER FRENCH ONION SOUP! Baby, YESSS! This stuff is so, so fantastic. I can’t even. I can only advise you to make it right away just to see what the delicious fuss is all about.

There are TWO WAYS to making this French Onion Soup; I will show you both ways:

  1. First, we can make it all in the crock pot, from beginning to end, and that will take a good 12 hours.
  2. Secondly, we can partially make it on the stove top and finish it off in the slow cooker.

It’s up to you as to how you want to make it.

Slow Cooker soup, crock pot french onion, caramelized onions

HOW TO MAKE FRENCH ONION SOUP IN THE SLOW COOKER

  1. You are going to grab 6 large onions and slice them… get ready for some real tears, but it’s all worth it, I promise. Sweet onions are best for this soup, but you can also use yellow onions, if that is all you have on hand.
  2. Transfer sliced onions to the slow cooker, add in melted butter, salt, pepper, and a bit of sugar. If using yellow onions, I advise to add about a teaspoon of sugar. If using sweet onions, 1/4 teaspoon is all you will need.
  3. Next, you are going to set the slow cooker on LOW and let it cook for like 8 hours, or until onions are browned and caramelized, just as you see them in that photo above. When I make this soup, I always start to prepare it around 10 pm, and then in the morning I just add the rest of the ingredients and finish it up in 4 hours.
  4. Right before serving, slice up a baguette, ladle soup into ovenproof bowls, place one slice of bread inside each bowl, sprinkle shredded gruyere cheese over the bread and soup, and broil for a couple minutes or until cheese is melted.

You can also make a quicker version of this soup by starting it off on the stove top:

French Onion Soup, caramelized onions

  1. Combine onions, butter, sugar, salt, and pepper in a large skillet, and cook the onions for about 25 minutes, or until browned and caramelized.
  2. Transfer the onions to the slow cooker, add in beef broth, wine, thyme, salt, and pepper, and cook for 6 hours on LOW.
  3. When soup is ready, ladle it into ovenproof bowls, place a slice of baguette in each bowl, top with shredded cheese, and broil for couple minutes, or until cheese is melted.

French Onion Soup in a bowl.

This soup is mostly served as a starter, but considering how good it is, I could make a meal out of it. Bring on the bread and cheese!

MORE SOUP RECIPES:

ENJOY!

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TOOLS AND INGREDIENTS USED IN THIS RECIPE

Spooning out French Onion Soup.

Slow Cooker French Onion Soup

Katerina | Diethood
This classic, hearty, DELICIOUS French Onion Soup is prepared in the crock pot, and it's loaded with incredible flavor, caramelized onions, and CHEESE!
5 from 4 votes
Servings : 6 serves
Prep Time 10 mins
Cook Time 11 hrs 40 mins
Total Time 12 hrs

Ingredients
  

  • 6 sweet onions, thinly sliced (you can also use yellow onions, but up the sugar to 1 teaspoon)
  • 4 tablespoons unsalted butter, melted
  • 1/4 teaspoon sugar
  • 1/2 teaspoon salt
  • 1/2 teaspoon fresh ground pepper
  • 4 to 6 sprigs fresh thyme
  • 1 bay leaf
  • 6 cups fat free, low sodium beef broth
  • 1/2 cup dry white wine
  • salt and pepper, to taste
  • 6 slices french bread optional
  • 1 1/2 cups shredded gruyere cheese, optional (if you can't find gruyere, use swiss cheese)

Instructions
 

  • Place sliced onions in a 6 quart slow cooker.
  • Stir in melted butter, sugar, salt, and pepper.
  • Top with thyme and bay leaf, COVER and cook on LOW for about 8 hours, or until onions are browned and caramelized. Stir half way through. 
  • Once onions are caramelized, stir in the beef broth and wine.
  • Taste for salt and pepper and season accordingly.
  • Cover and cook on LOW for 4 hours, or on HIGH for 2 hours, or until heated through.
  • Remove and discard thyme and bay leaf.
  • Turn the oven-broiler on High.
  • Ladle soup into ovenproof bowls.
  • Top the bowls with a slice of french bread and cheese.
  • Broil in oven until cheese is melted, about 2 to 3 minutes.
  • Serve.
  • Please see my notes for a lighter version of this soup, as well as a quicker cooking version. 

Notes

WW Freestyle SmartPoints without bread and cheese: 4
WW Freestyle SmartPoints with bread and cheese: 12
If watching your calorie/carb intake, omit the bread and cheese.
You can also make a quicker version of this soup by starting it off on the stove top:
  1. Combine onions, butter, sugar, salt, and pepper in a large skillet, and cook the onions for about 25 minutes, or until browned and caramelized.
  2. Transfer the onions to the slow cooker, add in beef broth, wine, thyme, salt, and pepper, and cook for 6 hours on LOW.
  3. When soup is ready, ladle it into ovenproof bowls, place a slice of baguette in each bowl, top with shredded cheese, and broil for couple minutes, or until cheese is melted.

Nutrition

Calories: 468 kcal | Carbohydrates: 62 g | Protein: 18 g | Fat: 15 g | Saturated Fat: 8 g | Cholesterol: 42 mg | Sodium: 360 mg | Potassium: 971 mg | Fiber: 4 g | Sugar: 18 g | Vitamin A: 425 IU | Vitamin C: 15.9 mg | Calcium: 240 mg | Iron: 3.4 mg | Net Carbs: 58 g

Nutritional info is an estimate and provided as courtesy. Values may vary according to the ingredients and tools used. Please use your preferred nutritional calculator for more detailed info.

Course: Soup
Cuisine: French
Keyword: crockpot french onion soup, french onion soup, french onion soup recipe, how to make french onion soup, slow cooker french onion soup
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29 comments on “Slow Cooker French Onion Soup”

  1. This was so good! I threw in some leftover pulled pork that I needed to use up. So good! It would have been good without it too! Thanks for the recipe!

  2. Love how easy this is to make in the slow cooker! Such a hearty and filling comfort food dinner for the family!

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